Statistics of polarization dependent loss in an installed long-haul WDM system

Abstract

We have made continual, multiple-day measurements of the polarization dependent loss of multiple C-band channels in an installed 1800 km terrestrial link. The PDLs of individual channels varied on the time-scale of hours, while the temporal variations of the PDLs of adjacent channels often tracked. The probability densities of the field measurements of PDL were not Maxwellian and instead were truncated, consistent with the limited number of elements in the link having appreciable PDL. A new model for the statistics of PDL in systems with few PDL elements is proposed, where a lower bound of the distribution exists if there is a dominant PDL element. The probability distributions from measurement and theory show good agreement.

Temporal Autocorrelation Functions of PMD Variables in the Anisotropic Hinge Model

“…4 instead displays the simulated ACF of the PMD vector with hinge rotation axes that are held invariant for all realizations together with the result of (12), which remains approximately valid even for fixed hinge axes. The sharp peak in the ACF at zero time shifts has been reported both for the temporal ACF for systems without hinges [1], [14], [16], [17] and for the measured ACF of the polarization dependent loss (PDL) [18]. Similarly, in Fig.…”

“…Defining and employing (7) generates the recurrence relation (18) The last expression on the RHS of (18) is given by as shown in (10) and (11). Hence, the recurrence relation can be expressed as (19) Employing this recurrence relation repeatedly, we obtain the hinge result (20)…”

All-optical nonlinear processing of both polarization state and intensity profile for 40 Gbit/s regeneration applications

“…In many fields of photonics, the light state of polarization (SOP) remains so far one of the most elusive uncontrolled variable, which can dramatically degrade the performances of current optical systems through polarization mode dispersion (PMD), polarization depending loss (PDL) or simply polarization depend components [1][2][3][4][5][6][7]. Therefore these deleterious polarization effects represent a serious issue for the development of future all-transparent networks, mainly because all-optical circuits, that will be inserted in those systems via silicon chip technologies [8][9][10], presently suffer from large polarization dependent performances.…”

Optical implementation of a space–time-trellis code for enhancing the tolerance of systems to polarization-dependent loss

“…Such decoding is fairly complex in optical communications rates, and, as the present work is motivated by alleviating complexity, we do not consider it here. Instead, taking advantage of the comparatively moderate fading caused by PDL in optical systems (the average PDL of a link rarely exceeds few decibels [6]), our proposed scheme relies on a very simple, albeit suboptimal, decoding scheme. We assume that the receiver consists of a digital equalizer followed by a fixed decoder implementing the relations…”

“…Although in both cases the signal is manipulated by a unitary transformation that involves the introduction of a DGD, the principles of operation are distinctly different. In the presence of PMD, the PDL vector itself (both direction and modulus) becomes frequency dependent, and its correlation bandwidth is known to be given by π∕τ [6,11]. Therefore, achievement of effective frequency averaging within the bandwidth of the information carrying signal requires that τ is well in excess of the symbol duration T s .…”